Preparation And Properties Of Epoxy Resin Composite Prepared By Injection Molding And Compression Molding

At present, the deep sea solid buoyancy material is generally use the epoxyresin as matrix, with the hollow glass microspheres as filler material, so the epoxyresin composite has low density and high compressive strength. The high-pressureenvironment of deep sea requires the composite has good properties of density andcompressive strength, at the same time, how to guarantee the uniformity of thecomposite has become a realistic problem that need to be solved.This paper uses two kinds of hollow glass microspheres as the lightweight filler,they are the K20(density:0.19g/cm3, compressive strength:3.45MPa, diameter D50:65μm, biggest diameter:120μm) and the HGS8000X (density:0.42g/cm3,compressive strength:55.2MPa, diameter D50:26μm, biggest diameter:55μm), theepoxy resin system is made in our laboratory, a series of composite materials withdifferent volume fraction of glass microspheres is prepared by injection molding andcompression molding.The density, compressive strength, water absorption and strength retention rateof different parts of the composite are tested respectively, and makes a detailedanalysis of its uniformity, the influence of HGM’s volume fraction on properties andtheir homogeneity of the composite is discussed. Results show that it can improvethe uniformity of density and compressive strength of the composite by mixing twokinds of hollow glass microspheres in a certain proportion that has differentdiameters, and it can reduce the density of the composite effectively by using hollowglass microspheres that has lower density instead of part of the hollow glassmicrospheres that has higher density. By changing the volume fraction of two kindsof hollow glass microspheres, it can prepare a series of composite materials bycompression molding, its density from0.542g/cm3to0.688g/cm3, and its compressive strength from34.4MPa to100.2MPa, which can be used in the waterdepth of2000m～11000m. At the condition of same hydrostatic pressure, thecomposite has smaller water absorption and higher compressive strength retentionrate if the hollow glass microsphere has higher compressive strength.The properties of the composites which are prepared by two kinds of moldingmethod are compared, and the influence of molding method on properties of thecomposites is discussed. Analysis shows that the injection pattern and pressure ofthe injection process are the main factors that influencing the performanceuniformity of the composite in the process of injection molding, and it requires highcompressive strength of the hollow glass microspheres in the process of injectionmolding. Compare with the method of injection molding, the composite has betterperformance uniformity that prepare by the method of compression molding, and inthe case of same volume fraction of the glass microsphere, it has lower density andhigher compressive strength. Besides, the using performance of the composite ismore stable that prepare by the method of compression molding.